#include "apue.h"
#include <dirent.h>	//该头文件中包含了opendir，readdir，closedir的函数原型

int main(int argc, char *argv[])
{
    DIR *dp;
 	struct dirent *dirp;
 	
 	if(argc != 2)
 	 	err_quit("usage:ls directory_name");
 	 	
	if((dp = opendir(argv[1])) == NULL)
 	 	err_sys("can't open %s", argv[1]);
 	while((dirp = readdir(dp)) != NULL)
  		printf("%s\n",dirp->d_name);
  		
 	closedir(dp);
 	exit(0);
}


































